Following the death of his wealthy parents in a fire, Roman Sionis inherited their fortune and attempted to run their company into the ground. However, this failed when his former childhood friend Bruce Wayne bought the company out. Sionis was filled with a bitter resentment toward Wayne.

Harboring an obsession with masks – symbolic and otherwise –, Sionis carved one from his father's black coffin and sought revenge on Wayne. This put him into conflict with Batman, and their battle eventually led to Sionis' mask being burned into his skin, remaking him Black Mask. He now operates as feared gang leader and one of the most powerful mob bosses in Gotham City, with an extreme hatred for Batman.